I think your first step may be to check with the manufacturer of the antennas. They probably have recommendations for stacking distances and may be able to offer pre-made cable assemblies for connecting them.
In general, the coaxes coming from each antenna need to be sized so that the signals from the two antennas combine in phase with each other. The optimum length will depend on the frequency of operation and the velocity factor of the coax being used.
The short answer is even if you gave us anything substantial to go on the answer is WAY beyond the scope of discussion on an internet forum. Take the above advice, stacking antennas and making power dividers (cable harnesses) is a science in itself.
"How long the coax had to be,and how far apart the Yagi Beams had to be apart."
One thing I can tell you whether you construct an H stack or diamond stack even at VHF what sits atop the tower is going to be HUGE and requires quite a substantial rotor to turn it.